Beam compass



Jan. 18, 1955 c. M. WOODWARD v Cflanencq, M. Woodward BEAM COMPASS Filed Oct. 27, 1952 I- S ITFEI; -1

United States Patent The present invention relates to improvements in drawing or drafting instruments, and more particularly it relates to the type of'instrument commonly referred to as a beam compass, which customarily comprises an extension beam to which a draftsmans compass may be attached readily so as to facilitate the scribing of curves having radii greater in length than the ordinary range of extended compasses as ordinarily provided in drafting sets.

A general object of the invention may be said to provide means for utilizing compasses as commonly provided in drawing instrument sets, especially the bow compass type.

A principal object of the invention is to provide an extension beam or beams of simple and substantial cons'truction and which provides for a reasonable degree of adjustment to vary the length of radii and which provides an extension compass beam which enables the attachment of an ordinary bow compass as the drawing element.

An additional and important object of the invention may be stated to be the provision of a drawing instrument "including an extensible beam to which may be attached at one end firmly the leg of a bow compass, and at the opposite end a stabilizing pivot pointassembly including supporting legsprojecting from opposite sides of the beam, and adapted to maintain the entire beam structure in operation.

Still more particularly, the invention provides channel clamp means movably mounted on a rectilinear beamfor mounting the drawing compass and also providing a mounting point about which the beam and compass may be rotated 'by one hand, there being provided adjacent to the said point means for enabling the beam and compass to remain upright even though unsupported by the hand 'ofthe operator, irrespective of the length of said beam.

A further specific object of the invention is to provide a beam compass which includes mounting clamp for the compass and other elements'which will be described hereinafter, whichclamps are provided with releasable interlocking means for securing the clamps in adjusted posit-ions -on the beam, wherein the said interlocking means although acting to secure the clamps to the beam, are nevertheless prevented from directly engaging the beam, the beam being protected against scarifying or other disfigurement produced by adjustments of the clamps along -the beam, such action in time marring thesurfaces of the beam to an extent such that adjustments of the clamps along the beam are obstructed or prevented altogether.

A still further specific object of the invention is to provide a plurality of cooperating clamps for the assembling of the bar compass of the present invention which include clamp devices adapted to tie together adjustment ends of similar bars in end-to-end relation for further increasing the effective length of the beam, the said clamp devices being of simple construction while at the same time tying together adjacent ends of the beams in a rigidly connected structure.

A further specific object of the invention provides im- ;proved clamps and beams interfitting therewith, which parts can be disassembled and packed in a case similar to an ordinary draftsmans kit, but without requiring dis mantling of the stabilizing pivot and base assembly from its clamp member, and also of the compass clamp member.

Further objects and advantages of the invention will become apparent as the description proceeds, and the features of novelty will be pointed out in particularity in the appended claims.

In connection with the present invention, it may be diameter and evenness. passes have been designed to be manipulated with one Patented Jan. 18, 1955 "ice pointed out that the instrument ofthe present invention comprises a compass which is provided with stabilizing means which enablethe compass to be manipulated with one hand even when drawing large circles. It is true that the ordinary draftsmans compass may be manipulated with one hand. This compass cannot be used, however, in drawing large circles and even inconnection with small circles it can be used efiiciently only by one skilled in drafting, and who, by reason of experience, has acquired the manual dexterity orknack of properly handling the instrument in order to produce a circle of uniform It is also true that 'beam comhand, such devices, however, have proven hard to handle and a certain degree of dexterity and familiarity therewith was necessary to obtain good results.

The construction of the present invention is entirely mechanical in its action and does not require any special skill or knowledge for its efficient use. It may be manipulated rapidly, the circles drawn therewith being clean and uniform and the line work even. The limits of the diameters of the circles which may be drawn are determined only by the length of the beam, and this may be adjusted as desired through the use of a joining clamp which is included as an element of the present construction. The present construction includes the utilization of a compass for the drawing point in drawing the circles, a pivot point structure which is designed to penetrate the surface on which the instrument is mounted and including a supporting member projecting laterally from opposite sides of the beam or bar and movable into longitudinal alignment with the bar when not in use for operation, a rectangular bar, and means for detachably mounting the compass and pivot point on the beam or bar. The invention contemplates the provision of a beam-type compass instrument with its component parts adapted to be packed as a drafting kit in a compact box for ready carrying,

The invention will be understood more readily by reference to the accompanying drawings, in which:

Fig. 1 is a side elevation of the assembleddevice.

Fig. 2 is an end view of Fig. l with the pivot point and supporting base membe'rin operative position.

Fig. 3 is a fragmentary top plan view of the pivot end portion of Fig. l, with the supporting member shownin dotted outline in inoperative position, in alignment with the beam, line 33, Fig. 2..

Fig. 4 is a plan view of the disassembled base supportin g member.

Fig. 5 is a side elevation of the beam-clamping channel assembly and compass-clamping extension thereof, as shown at the right hand end of Fig. 1, the compass to be gourlited in the extension being shown in dotted lines in Fig. 6 is an end view of the assembly of Fig. 5, looking towards the left as viewed in Fig. 5 along the line 66 of Fig. 5, looking in the direction of the arrows.

Fig. 7 is a top .plan view of the beam-clamping channel assembly and compass-clamping extension thereof as viewed in Fig. 5 along line 7-7 of Fig. 5 looking in the direction of the arrows.

Fig. 8 is a side View of a disassembled compass-clamping auxiliary channel.

Fig. 9 represents a view of the present device dismantled and packed in a case similar to a conventional draftsmaris kit of drawing instruments or tools, the view showing the container opened to display the contents of the kit.

Referring more particularly ot the drawings, reference letter A represents a beam or barof any desired length and cross-sectional dimension, which is illustrated as having portions broken out to fit in the drawings. In practice, the beam A is usually made of wood and is selected to be of proper 'size to receive a plurality of channel members B, C, and -D, which are composed of a suitable metal such as brass, bronze or the like, the

metal ch'annels'ha'ving top and bottom flanges which overlap the top and bottom edges of 'the bar A. The top flanges of these channels are spaced from the top side-of to interfit with the threads on .and perform functions which will be apparent as th channel element has a channel body 1, having an upper flange 2 and a lower flange 3, the body 1 being short but 7. member B and is provided with two set screws 22 and substantially greater in height than is the beam A, so

that when the bottom flange 3 engages the bottom edge of the beam A, the top flange 2 will clear the top edge of the beam A sufliciently to allow the insertion of a short and small complemental or auxiliary channel 4 between the said top flange 2 of the channel, and the top edge of the beam A, as viewed in Fig. 2. The complemental channel has top and bottom flanges 4 and '5 which extend parallel from the body member 6 of this complemental channel, between which flanges is received the top flange 2 of the channel B.

The top flange 4 of the complemental channel has a hole tapped therethrough for the reception of a locking thumb screw 7, the end of shank 8 of which presses against the bottom flange of the complemental channel and presses against this bottom flange to expand the flanges 4 and 5 of the complemental channel 4, thus locking the channel B in position on the beam A. It will be understood that the hole tapped through the top flange 2 of the channel member B is internally threaded the shank 8 of the locking screw 7, and a coil spring 9 is compressed between the upper flange 4 of the complemental channel and the head 10 of the thumb screw 7, this spring serving as a stabilizing retainer member for the channel 6 when the instrument is dismantled or inoperative. The screw 7 therefore serves as a set screw for locking the channel member B in desired position on the beam A, but because of the interposition of the bottom flange 5 of the channel 4 against which the end of the set screw 7 abuts when it is in locking position, the beam A is protected against wear and scoring which Would occur if the end of the set screw were to engage the top surface of the beam. Thus the provision of the complemental channel 4 protects the beam A against damage and wear.

The lower flange 3 of channel B is the mounting means for an important feature of the present invention.

In the bottom flange 3 is tapped a hole 11 which receives shank 12 of a short set screw 13, the head 14 of which is provided with a hole which receives a pointed pivot in 15 that is held in place by a headless set screw 16. This pin 15 is the point of rotation for the beam A when the appliance is in service, the headless set screw entering into an internally threaded hole provided therefor laterally in the head 14 of set screw 13. Intermediate the bottom flange 3 of the channel B and head 14 of the bottom set screw 13, there is mounted a base member 17 which is held by the shank 12 of the bottom set screw 13, and which is freely rotatable about the shank 12 of the set screw, when the compass is not in use, but which is restrained firmly in perpendicular position relative to the beam of the compass when the compass is being used to draw a circle or an arc thereof. This base member 17 .has a flat portion 18 and has a hole 18 therethrough for receiving screw 13 from which flat portion divergingly extend the leg members 19 and 20 which are designed to project sufl'lciently far beyond the sides of the beam A l to enable this beam to be self supporting in operative position when the base member 17 is turned until the legs 19 and 20 are at substantially right angles to the beam A. The legs 19 and 20 are turned upwardly adjacent to their ends to define feet or rests 21 and 21.

The base member 17 is made from strip metal, the width of which preferably is not greater than the width of the bottom surface of the beam A so that when the base member is turned on set screw 13 to parallel the under side of the beam A no portion of the base member 17 will extend beyond the planes of the sides of the beam A, so that the beam A will lie flat on its side when not in use, but when turned to its supporting position with the legs 19-and 20 at right angles to the beam A, it will hold the beam upright in stable equilibrium without re- 23, which are similar to the aforesaid set screw 7 of the channel member B. These set screws 22 and 23 operate through complemental channels which are entirely similar to the complemental channel 4 interfitting with the channel member B as has been described above. The heads of these set screws are indicated at 24 and 25 respectively, and coil springs 26 and 27 are compressed between their heads and the top flange of the complemental channel, these springs 26 and 27 being entirely similar to the above described spring 9 provided for the set screw 7 and perform the same function. This channel member C with its dual set screws is employed to join together similar ends of beam A and a similar beam A, when it is desired to increase the length of the beam A. As will be seen from Fig. 1, a portion of the second beam A is indicated as being broken out for shortening the beam to the dimensions of the sheet of drawing.

At the free end of the second beam A is positioned the channel D, this being shown at the right-hand end of the second beam A as viewed in Fig. 1. A set screw 28 is provided for this channel member D, this screw 28 passing through hole 28 provided for it in top flange 29 of complemental channel 31 (Figs. 5 and 7) and there is provided a coil spring 29 which is associated with the set screw 28 and compresses beneath the screw head 30, this spring 29 being similar to the aforesaid springs, for example, the spring 9, and performs the same function.

lnterfitting with the channel member D and set screw 23 in a manner entirely similar to the complemental channel 4 is the auxiliary channel 31, the bottom flange 32 (Fig. 5) of which forms the abutment surface for the end of the set screw 28, this bottom flange 32 being extended beyond the end of the beam A and then bent downwardly in an approximately right-angled elbow 33, this flange 32 being continued further as a bottom (or inner) flange 34 of channel 35, which is shown as being integrally depending from the complemental or auxiliary channel 31, and which has flange 36 as an upper .(or outer) flange which parallels flange 34. This flange 36 interfits with a short complemental channel 37, a set screw 38 passing through suitable holes 38 and 39' provided therefor in channel 37 and flange 36. The screw 38 interfittingly extends through the flange 36 and abuts against flange 37, the channel 37 and set screw 38 forming a locking means for a leg 39 of a compass E (Fig. l), the leg 39 being secured between the flange 37 (Fig. 7) of channel 37, and the flange 34 of channel 35, tightening of the set screw 38 firmly locking the leg 39 of the coming leg 40, which leg is provided with a drawing point 42.

that engages the surface of drawing paper or other surface on which the arcs or circles are being drawn.

It will be understood from the foregoing description that the entire assembly which has been described above, may be dismantled completely by releasing the respective set screws, thereby disassembling'the complemental channel members B, C, and D, which then may be slipped off from the previously interlocked beams A and A which then may be taken apart. The disassembled elements then may be packed in a box' 43 as a drafting kit, as indicated in Fig. 9, the case 43 shown open with partial cover flaps 44 and 45, and being provided with recesses or compartments for receiving the individual units of the assembly.

In Fig. 3, the full lines show the operative position of the base member 17, the dotted lines show the extended inoperative position or case packing position thereof.

From the above it will be apparent that I have designed a beam compass extensible to any desired length up to several feet, having means at one end for pivotally supporting the compass in upright position whereby it may be readily manipulated by a single draftsman, said device being simple in construction, easily assembled, so constructed that adjustment of the parts will not mar or that various minor changes in details of construction, proportion and arrangement of parts, may be resorted to within the scope of the appended claims without departing from or sacrificing any of the principles of this invention.

Having thus described the invention, what is desired protected by Letters Patent is as set forth in the following claims.

What is claimed is:

1. A beam compass for drafting, combination, an elongated beam, member mounted on the beam and beam to a selected position,

which comprises, in a principal channel adjustable along the the principal channel member having an upper flange and a lower flange, the said flanges straddling the beam, a complemental channel having upper and lower parallel flanges straddling the upper flange of the principal channel member, the lower flange of the complemental channel being positioned intermediate the upper flange of the principal channel member and the beam, releasable locking means adjustably mounted in the upper flange of the complemental channel and the upper flange of the principal channel member, the said locking means engaging the lower flange of the complemental channel for expanding the complemental channel into locking position on the beam, a set screw extending through the lower flange of the principal channel member, a head on the set screw, a pointed pivot pin mounted in the head, and a base member for the beam mounted on the set screw and having a substantially planar middle section and leg elements diverging from the planar middle section and terminating in rest position adapted to seat on the drafting surface, the said base member being rotatable around the set screw be tween operative supporting position at substantially right angles to the beam and inoperative position with the leg elements and planar middle section substantially parallel to the beam, the said pivot pin engaging the drafting surface for enabling rotation of the beam around the pivot pm.

2. A beam compass for drafting, which comprises, in combination, an elongated beam, means adjacent to an end of the beam for supporting the beam and for rotatably applying the beam to a drafting surface, and compasscarrying instrumentalities mounted on the beam adjacent to an end of the beam opposite to the aforesaid end, the said instrumentalities including a principal channel member having a top flange and a bottom flange straddling the beam, a complemental channel with top and bottom flanges straddling the top flange of the principal channel member, with the bottom flange of the complemental channel intermediate the top flange of the principal channel member and the beam, releasable locking means threadedly mounted in the top flange of the principal channel member and bearing against the bottom flange of the complemental channel for locking the bottom flange and top flange of the principal channel member, the bottom flange of the complemental channel member being projected beyond the end of the beam and then bent into a depending elbow at approximately right angles to the longitudinal axis of the beam, the said flange being further extended into a lower flange of a second complemental channel having an upper flange parallel to its lower flange, a third complemental channel having parallel flanges straddling the upper flange of the second complemental channel, releasable locking means extending through the upper flange of the third complemental channel and also the upper flange of the second complemental channel, and a drafting compass having a leg positioned between the lower flange of the third complemental channel and the lower flange of the second channel, the locking means for the said third complemental channel expanding the lower flange thereof for lockingly clamping the leg of the compass between the lower flanges of the third and second channels.

3. A beam compass assembly as claimed in claim 2, which comprises locking means for connecting together adjacent ends of similar beam sections, said locking means including a principal channel member bridging the adjacent ends of similar beam sections, a complemental channel mounted on the principal channel member intermediate a top flange thereof and the beam sections, and dual locking means threadedly mounted in the flange of the principal channel member and engaging a lower flange of the complemental channel for expanding the latter in locking engagement with the sections of the beam, there being one of the locking means for each section of the beam for interlocking the sections of the beam together.

4. A beam compass assembly as claimed in claim 3, wherein the locking means for connecting together adjacent ends of similar beam sections comprise set screws having enlarged heads and shanks extending through the upper flanges of the complemental channel and of the principal channel member and threadedly mounted in the latter, and coil spring means compressed between the scrlew heads and the top flange of the complemental channe 5. A beam compass as claimed in claim 4, wherein the principal channel members and said means for sup porting the beam and rotatably applying the beam to a drafting surface are demountable from the beam sections, the respective units of the compass assembly after being demounted being adapted to be received in a container provided with compartments for each of said units, whereby said separated units may be packaged as a kit.

References Cited in the file of this patent UNITED STATES PATENTS 2,567,265 Woodward Sept. 11, 1951 

